I'm doing a project of sorting objects, and this is the first time i'm working with microcontrollers. I am using AT89C52 microcontrollers. i just couldn't understand these statements in the datasheets. "When 1s are written to Port 2 pins they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pullups." how am i supposed to use the port as inputs? what should i do when i want the pins as inputs, and also, what should i do when i want the pins as outputs? the port is an I/O pin. since i would be using the T2 and T2EX timers, can i simultaneously using some of port 2 pins as input (timer/counter) and the others as output? The datasheets could be obtained from www.atmel.com Thx b4.